Improvement of cardiomyocyte function by a novel pyrimidine-based CaMKII-inhibitor
Pathologically increased activity of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and the associated Ca2+-leak from the sarcoplasmic reticulum are recognized to be important novel pharmacotherapeutic targets in heart failure and cardiac arrhythmias. However, CaMKII-inhibitory compounds for t...
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Published in | Journal of molecular and cellular cardiology Vol. 115; pp. 73 - 81 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Elsevier Ltd
01.02.2018
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Subjects | |
Online Access | Get full text |
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Summary: | Pathologically increased activity of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and the associated Ca2+-leak from the sarcoplasmic reticulum are recognized to be important novel pharmacotherapeutic targets in heart failure and cardiac arrhythmias. However, CaMKII-inhibitory compounds for therapeutic use are still lacking. We now report on the cellular and molecular effects of a novel pyrimidine-based CaMKII inhibitor developed towards clinical use.
Our findings demonstrate that AS105 is a high-affinity ATP-competitive CaMKII-inhibitor that by its mode of action is also effective against autophosphorylated CaMKII (in contrast to the commonly used allosteric CaMKII-inhibitor KN-93). In isolated atrial cardiomyocytes from human donors and ventricular myocytes from CaMKIIδC-overexpressing mice with heart failure, AS105 effectively reduced diastolic SR Ca2+ leak by 38% to 65% as measured by Ca2+-sparks or tetracaine-sensitive shift in [Ca2+]i. Consistent with this, we found that AS105 suppressed arrhythmogenic spontaneous cardiomyocyte Ca2+-release (by 53%). Also, the ability of the SR to accumulate Ca2+ was enhanced by AS105, as indicated by improved post-rest potentiation of Ca2+-transient amplitudes and increased SR Ca2+-content in the murine cells. Accordingly, these cells had improved systolic Ca2+-transient amplitudes and contractility during basal stimulation. Importantly, CaMKII inhibition did not compromise systolic fractional Ca2+-release, diastolic SR Ca2+-reuptake via SERCA2a or Ca2+-extrusion via NCX.
AS105 is a novel, highly potent ATP-competitive CaMKII inhibitor. In vitro, it effectively reduced SR Ca2+-leak, thus improving SR Ca2+-accumulation and reducing cellular arrhythmogenic correlates, without negatively influencing excitation-contraction coupling. These findings further validate CaMKII as a key target in cardiovascular disease, implicated by genetic, allosteric inhibitors, and pseudo-substrate inhibitors.
•AS105 is a novel, pyrimidine-based ATP-competitive CaMKII-inhibitor.•It is in this manner also effective against autophosphorylated CaMKII (as opposed to KN-93).•AS105 does not negatively affect basal excitation-contraction-coupling in cardiomyocytes.•In cardiomyocytes from CaMKIIδC-overexpressing mice with heart failure, AS105 reduces SR Ca2+-leak, thus improving SR Ca2+-accumulation, leading to improved systolic function.•AS105 also reduces SR Ca2+-leak in human atrial cardiomyocytes, suppressing arrhythmogenic single cell Ca2+-events. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-2828 1095-8584 |
DOI: | 10.1016/j.yjmcc.2017.12.015 |